1. Field of the Invention
The invention relates to a microelectronic position sensor, e.g for use in hearing aids and the like for volume control, function shifts or changes of another adjustable parameter of the associated apparatus, said position sensor operating by means of magnetic field sensitive elements and comprising a stationary base portion or stator which contains magnetic field sensitive elements and an adjustment means or rotor which is rotatably mounted and contains a permanent magnet, and wherein the stator is electrically coupled to the associated apparatus by means of a plurality of electrically conductive terminals which are embedded in the stator, said stator comprising an integrated circuit on which the magnetic field sensitive means are arranged for providing an electrical signal depending on the position of the permanent magnet and hence of the rotor.
2. Related Art
A position sensor of the above mentioned type is disclosed in U.S. Pat. No. 4,415,856. This prior art sensor has its rotor mounted through an aperture in a panel of a housing. The stator integrated circuit placed in a dual-in-line package (DIP) is mounted on a printed circuit board in the housing below the rotor. Such DIP member is a standard component having a size of approx. 10.times.6 mm with a distance between its four terminals on each side of approx. 2.5 mm. The mutually independent mounting of the stator and rotor implies a considerable distance between the magnet of the rotor- and the magnetic field sensitive elements in the stator which is detrimental to a reliable and precise operation. This again, however, has the adverse effect of increasing the required size of the permanent magnet for obtaining a sufficient magnetic response of the sensitive elements. The total height of a sensor of this kind is large due to the above indicated structural features and the termination method to be used on the DIP member.
A position sensor of the above mentioned type is, through its integral circuits, particularly suitable for providing digital output signals, which is important when the remaining circuits of an equipment are entirely or partially based on such signals. However, this known Hall effect position sensor is not suitable--nor--meant--for microelectronic use where the outer dimensions of a e.g. for use in hearing aids, should not exceed a magnitude of 3.4 mm, neither in diameter nor in height, and therefore it does not offer a solution of position sensors of such size and having sufficiently accurate operation positions. The same applies to other known embodiments of Hall effect position sensors or rotary switches, cf. e.g. U.S. Pat. Nos. 4054860, 4054861, 4199741, and 4459578 and DE patent publication No. DE-A-3908892.
Electronic pulse generators for microelectronic use e.g. in hearing aids are known from the Applicant's Danish patent applications Nos. 1838/90 and 52/91. Although the inventions according to applications relate to a development of such pulse towards an increasingly simple and at the same time electronically more reliable electromechanical construction, they are, precisely from a construction point of view, comparatively complex with the ensuing risks of malfunction during use thereof in hearing aids, and correspondingly costly to produce.